The invention is directed to a process for the solidification and elimination of radioactive borate containing solutions and suspensions, which accumulate as evaporator concentrates in the operation of pressurized water reactors, by the addition of liquid or solid additives which make possible a setting of the hydraulic binder which is also added.
The cementing of radioactive waste liquids is known as a suitable and approved process for conversion into a solid, transportable and final storable form. However, it has been found problematical for solutions containing more than 5% of solid substances and more than 5% boric acid or borate because cracked and crumbly compositions form and the liquid frequently is not completely set.
Furthermore, it is known (ASME Publication 74-WA/NE-9) that borate containing solutions and suspensions cannot be hardened to compact blocks by mere addition of cement. In the literature (ASME Publication 74-WA/NE-9), the addition of water glass is recommended but with solutions of (a) more than 5% borate component and (b) suspensions with more than 5% solids this does not lead to the desired result.
Therefore, there has already been proposed a process of treating the radioactive borate containing solutions with bone glue, drying on heated rolls with the addition of polyacrylamide and pressing the rolled stock, see Dollgast, German Pat. No. 17, 64, 586. In this manner solid substances can be produced, but in the drying waste gas problems develop because of the escaping vapor.
Furthermore, it has been proposed to evaporate borate containing waste solutions to such an extent that the remaining water is bound as water of crystallization, Kausz, German Pat. No. 17, 67, 184. Thereby waste gas problems likewise occur and besides, the sodium borate formed is not stable to leaching.
Therefore, it was the problem of the present invention to find a process for the solidification and elimination of borate containing aqueous liquids having a borate content above 5% and a solids content above 5% which permits the production of compact, transportable and final storable waste substances without requiring evaporation and drying steps in order to avoid the waste gas and waste water problems and also completely binds the aqueous liquid by additives.